1. Field of the Invention
The present invention relates to an image-transfer medium suitable for use in forming an image on a transfer-printing medium by transfer printing, a process for producing a transferred image using this image-transfer medium, and a cloth with a transferred image formed thereon, and more particularly to an image-transfer medium suitable for use in an ink-jet recording method using, particularly, water-based inks upon forming an image on a coloring material-retaining layer making up the image-transfer medium, a process for producing a transferred image by using such an image-transfer medium by transferring the coloring material-retaining layer having an image thereon to a transfer-printing medium, thereby forming the transferred image, and a cloth with a transferred image formed thereon by the production process.
2. Related Background Art
As typical ink-jet printing systems using water-based inks, various ink ejection systems are known, for example, an electrostatic attraction system, a system in which a piezoelectric element is used to give an ink mechanical vibration or change, and a system in which an ink is heated to form bubbles in the ink, thereby using the pressure thus produced. The printing is conducted by, generating and ejecting minute droplets of an ink by one of these ink ejection systems and applying parts or all of the droplets to a recording medium. Such an ink-jet printing system attracts attention as a simple system which produces minimal noise and can conduct high-speed printing and color printing. In recent years, ink-jet printers making good use of such a system, by which color printing can be simply conducted, have become widespread.
In recent years, there also has been an increasing demand for conducting color printing on various recording media using these printers. In order to meet such a demand, particular attention is paid to printing techniques in which an image is formed on an image-transfer medium (image-transfer paper) by an ink-jet printing system, and the image is then transfer-printed on another transfer-printing medium so that printing can be conducted irrespective of the form of transfer-printing media, namely, the formation of an image can be performed on any medium which does not permit direct printing by a printer.
Some image-transfer media making good use of an ink-jet printing system to form an image thereon have been proposed to date. Japanese Patent Application Laid-Open No. 8-207426 has proposed an ink-jet printing sheet in which an ink-receiving layer is composed of a thermoplastic resin, a crystalline plasticizer and a tackifier, thereby permitting sticking a transferred image to a transfer-printing medium by heating alone. Japanese Patent Application Laid-Open No. 8-207450 has proposed an image-transfer medium in the form of a sheet, comprising a base material layer and a heat transfer layer which is composed of a particulate thermoplastic resin, inorganic porous fine particles and a binder and permits ink-jet printing and heat transfer printing. U.S. Pat. No. 5,501,902 has proposed an image-transfer medium for ink-jet, comprising a transfer layer of a structure that a cationic resin, an ink-viscosity adjuster and the like are added in addition to the above-described components.
However, these image-transfer media according to the prior art have not been able to satisfy suitability for ink-jet printing, simplification of transfer printing, fastness properties of images transfer-printed on transfer-printing media, and the like at the same time. Therefore, in Japanese Patent Application Laid-Open No. 10-16382, the present inventors proposed an image-transfer medium comprising a base material, a releasing layer and a transfer layer.
The image-transfer medium described above has been well balanced among the suitability for ink-jet printing, simplification of transfer printing and fastness properties of the transferred image. When an image printed on the image-transfer medium is transfer-printed on a flexible transfer-printing medium, for example, a cloth or paper, however, such an image-transfer medium has not been said to be satisfactory in point of forming a high-quality transferred image without impairing the hand and touch inherent in the transfer-printing medium at the portion on which the transferred image has been formed. In particular, this tendency has become more pronounced when the image-transfer medium is used in a high-image quality color printer, since the transfer layer must be thickened due to increased shot-in ink quantity. In addition, although this image-transfer medium is excellent in point of the simplification of formation of a transferred image, because it has a releasing layer, and so a base material can be removed with ease after transfer printing, it takes a long time to transfer the transfer layer great in thickness like the above-described case in the case where transfer printing is conducted with the image-transfer medium of large size by means of a household iron or the like. Therefore, the image-transfer medium has not been said to be satisfactory also with respect to everyone being able to form a transferred image of large size in good condition.